The present invention relates to a contact in which a spring connector is disposed substantially in parallel with a circuit board.
Referring to FIGS. 11A to 12, an example of a related-art contact in which a spring connector is disposed substantially in parallel with a circuit board will be briefly described. FIGS. 11A, 11B and 11C show an outer appearance of the related-art contact, in which FIG. 11A is a front view, FIG. 11B is a bottom view, and FIG. 11C is a side view. FIG. 12 is an enlarged sectional view taken along a line A-A in FIG. 11B, in which an internal structure of an electrically conductive metal tube is omitted. In FIGS. 11A to 12, each of spring connectors 10 includes a conductive metal tube 12 which is open at one end and closed at the other end, a spring coil (not shown) which is inserted into the conductive metal tube 12 from the open end side, and a plunger 14 formed of conductive metal which is additionally inserted into the conductive metal tube 12. The open end of the conductive metal tube 12 is narrowed so that the plunger 14 can move in an axial direction having its distal end portion projected outward from the open end, but may not escape. Moreover, an insulating housing 16 formed of insulating resin or the like substantially in a shape of a box is provided with bottomed insertion holes 16a which are in parallel with a bottom face thereof and open at a side of the bottom face in a shape of slit in the axial direction. The spring connectors 10 are respectively inserted into these insertion holes 16a, and portions of outer peripheral faces of the respective conductive metal tubes 12 are slightly protruded from the openings on the bottom face of the insulating housing 16, whereby the contact is constructed. The contact having the above described structure is mounted on the circuit board, and the portions of the outer peripheral faces of the conductive metal tubes 12 which are protruded from the bottom face of the insulating housing 16 are soldered to connecting terminals of the circuit board by solder reflowing or the like, whereby electrical connection is established. An art similar to the related art having such structure is disclosed in JP-A-2000-195600.
In the structure of the related-art contact as described above, as shown in FIG. 12, a height H of the contact from a soldered face of the circuit board is a sum of an outer diameter D of the conductive metal tube 12 and a thickness T of the insulating housing 16 at a position where it covers this conductive metal tube 12. Recently, a mobile phone or the like becomes more and more compact and thin, and therefore, it is keenly desired that the contact is also made thinner. However, in order to reduce the outer diameter D of the conductive metal tube 12, it is required that the spring coil and the plunger 14 incorporated therein are made compact. This is technically difficult, and makes production difficult. Besides, by reducing the thickness T of the insulating housing 16 at the position covering the conductive metal tube 12, mechanical strength of the insulating housing 16 would be weakened, and this has a limit in itself. It is to be noted that the contact having the above described structure is used, as an example, for electrical connection of battery packs in electronic appliances and so on.